During operation of an engine assembly, small amounts of gases may leak out of the cylinders of the engine into the engine crankcase. Such gases are referred to as blow-by gases. In order to prevent a build-up of blow-by gases within the crankcase, engines typically comprise a crankcase ventilation system, such as a Positive Crankcase Ventilation (PCV) system, configured to extract gases from within the crankcase. The PCV system utilizes a low pressure created in the intake system of the engine assembly to draw the blow-by gases out of the crankcase. The extracted gases may be reintroduced into the inlet of the engine assembly.
The blow-by gases may contain oil, e.g. oil mist. It may be undesirable for the oil to be reintroduced to the inlet of the engine assembly. Hence, the PCV system may comprise an oil separator configured to separate the oil from the gases. The separated oil may be returned to an oil sump of the engine assembly.
The blow-by gases are typically extracted from the crankcase at a cylinder head of the engine assembly and the oil separator may be mounted on or close to the cylinder head. The oil that has been separated from the blow-by gases by the oil separator may drain back through an oil drain passage formed in one or more housings of the engine assembly to an oil sump.
For some configurations of engine assembly, such as a naturally aspirated engine assembly, the PCV system may comprise a single oil separator and the separated oil may drain back to the sump via a single oil drain passage formed within housings of the engine assembly. For other configurations of engine assembly, such as a turbocharged engine assembly, the PCV system may comprise two oil separators and two oil drain channels may be formed within the housings to allow the oil from each of the oil separators to drain back to the oil sump of the engine assembly.
According to an aspect of the present disclosure, there is provided an engine housing component, the housing component defining two or more drain channels configured to receive oil separated from a crankcase ventilation system and to drain said oil through the housing component, wherein the engine housing component comprises two or more drain features, each of the drain features corresponding to one of the drain channels, wherein each of the drain features is configured to allow an oil drain pipe to be coupled to the drain feature such that the oil drain pipe is in fluid communication with the corresponding drain channel, wherein a first drain feature differs from the or each of the other drain features, such that a particular oil drain pipe configured to couple to the first drain feature is not couplable to the other drain features.
Each of the drain features may comprise: a drain port in fluid communication with the corresponding drain channel; and a coupling separate from the drain port, wherein the coupling is configured to allow the oil drain pipe to be coupled to the drain feature.
The configuration, e.g. the size and/or shape, of the drain port of the first drain feature may be different from the configuration of the drain port of the other drain features. Additionally or alternatively, the configuration, e.g. the size and/or shape, of the coupling of the first drain feature may be different from the configuration of the coupling of the other drain features. Additionally or alternatively again, the relative positions of the drain port and coupling of the first drain feature may be different from the relative positions of the drain ports and couplings of each of the other drain features. For example, a distance, e.g. a center distance, between the coupling and drain port of the first drain feature may differ from the distance between the couplings and drain ports of the other drain features.
The coupling may comprise a bore configured to receive a fastener provided on the drain tube. The bore may comprise a threaded portion and the drain tube fastener may be threaded into the bore.
To avoid unnecessary duplication of effort and repetition of text in the specification, certain features are described in relation to only one or several aspects or embodiments of the disclosure. However, it is to be understood that, where it is technically possible, features described in relation to any aspect or embodiment of the disclosure may also be used with any other aspect or embodiment of the disclosure.